This invention relates to a method and apparatus for the positioning and setting of a magnetic head in a tape drive assembly for accurate tracking of magnetic tape contained in a cassette, the cassette being adapted to be received in the tape drive assembly.
The use of magnetic tape cassettes is common in the computer industry, where such magnetic tape has a defined width, and a number of tracks, wherein information can be written and subsequently read by appropriately positioned magnetic heads. There is a tendency to provide an increasing number of tracks on a strip of magnetic tape to maximize the amount of information which may be contained therein. As a result of this increasing number of tracks, it has become more and more critical that locating a particular track is carried out with speed and accuracy for precision reading of information contained in that track. By "locating" a particular track is meant that a magnetic read or write head be positioned with respect to the magnetic tape so that the head accurately and precisely corresponds with the track for efficient retrieval of the information thereon.
In order for the magnetic head to read from or write onto a track, it is necessary that the tape drive assembly provide a mechanism whereby the tape head can be displaced in a direction normal to the movement of the tape so that the tape head can move up and down across the width of the tape for the purposes of locating a track. Typically, a head carriage assembly is mounted on a spindle or shaft which may be rotated by a motor, the spindle being threaded and engaging a threaded bore in the head carriage assembly. Rotation of the spindle results in up and down movement of the magnetic head. In order to insure maximum read/write efficiency, the precise orientation and position of the magnetic head should be properly set, and the motor driving the head carriage assembly must be accurately programmed so as to stop the magnetic head in a manner which will cause it to directly register with or correspond to a desired track.
It is the purpose of the present invention to provide a method and apparatus which permit custom setting and programming of a particular tape drive assembly. The invention therefore relates to a method and apparatus which permit accurate setting of the orientation of the magnetic head on the carrier, as well as a method and apparatus designed to measure and program the tape drive assembly to accurately locate a particular track on the magnetic tape, taking into account the particular tolerances of the specific tape drive assembly.